Rheem 874W27NF - Fault Finding

22
TM061 Rheem 27 Water Star Service Instructions – Issued: 11/10
REV A Issued 08/13
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”
THERMISTOR RESISTANCE CHART
Temp °C
Resistance
KΩ
Temp °C
Resistance
KΩ
Temp °C
Resistance
KΩ
Temp °C
Resistance
KΩ
0
23.73
25
8.494
50
3.485
75
1.598
1
22.706
26
8.177
51
3.371
76
1.552
2
21.733
27
7.873
52
3.262
77
1.508
3
20.806
28
7.583
53
3.156
78
1.465
4
19.925
29
7.304
54
3.055
79
1.424
5
19.085
30
7.037
55
2.957
80
1.384
6
18.286
31
6.781
56
2.863
81
1.345
7
17.525
32
6.536
57
2.773
82
1.307
8
16.799
33
6.302
58
2.686
83
1.271
9
16.108
34
6.076
59
2.602
84
1.236
10
15.449
35
5.86
60
2.52
85
1.202
11
14.82
36
5.653
61
2.442
86
1.169
12
14.221
37
5.454
62
2.367
87
1.137
13
13.469
38
5.264
63
2.295
88
1.106
14
13.104
39
5.081
64
2.225
89
1.077
15
12.583
40
4.905
65
2.157
90
1.048
16
12.086
41
4.736
66
2.092
91
1.02
17
11.611
42
4.574
67
2.029
92
0.993
18
11.157
43
4.418
68
1.968
93
0.966
19
10.723
44
4.269
69
1.91
94
0.941
20
10.309
45
4.125
70
1.853
95
0.916
21
9.913
46
3.987
71
1.799
96
0.893
22
9.534
47
3.854
72
1.746
97
0.869
23
9.172
48
3.726
73
1.695
98
0.847
24
8.826
49
3.603
74
1.646
99
0.825
FAULT FINDING
When measuring resistance of a part, turn off the electric power and be sure to
disconnect the part completely before measuring (from connector or terminal).
Resistance checks are performed on the part while it is disconnected from the
control board.
“Live” testing to be conducted. Personal Protective Clothing (PPE) shall be
worn to reduce the risk of electric shock. Refer to Rheem Safety Procedure
on electrical testing.
All Molex connections only go to one location and fit one way. You do not need to
force a connection.
CAUTION: When performing maintenance and/or servicing the water heater,
wait for the water heater to become cool. Be careful to avoid injury on the
sharp edges.